α-Diazoacetates as carbene precursors:: Metallosalen-catalyzed asymmetric cyclopropanation
α-Diazoacetates as carbene precursors:: Metallosalen-catalyzed asymmetric cyclopropanation
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DOI：
10.1055/s-2006-926448
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发表时间：
2006-05-15
影响因子：
2.6
通讯作者：
Katsuki, Tsutomu
中科院分区：
文献类型：
--
作者：
Uchida, Tatsuya;Katsuki, Tsutomu
容易获得的α-重氮化合物已被证明是使用钌（NO）-salen和钴-salen络合物作为催化剂的不对称环丙烷化的有效卡宾前体。环丙烷化的立体选择性取决于金属离子、其价态、salen配体的结构和电子性质以及所用salen络合物的顶端配体。在温和的条件下，通过使用合适的金属salen配合物，可以实现反式和顺式选择性的分子间不对称环丙烷化反应。此外，广泛的链烯基α-重氮乙酸酯和相关的链烯基重氮甲基酮通过使用以模块化方式容易制备的各种金属salen络合物作为催化剂以高度对映选择性的方式进行分子内环丙烷化。
Readily available a-diazo compounds have been shown to be efficient carbene precursors for asymmetric cyclopropanation using ruthenium(NO)-salen and cobalt-salen complexes, as catalysts. The stereoselectivity of the cyclopropanation depends on the metal ion, its valency, the structural and electronic nature of the salen ligand, and the apical ligand of the salen complex used. Both trans- and cis-selective asymmetric intermolecular cyclopropanation can be realized under mild conditions by using a suitable metallosalen complex. Furthermore, a wide range of alkenyl alpha-diazoacetates and the related alkenyl diazomethyl ketones undergo intramolecular cyclopropanation in a highly enantioselective manner by using various metallosalen complexes, easily prepared in a modular fashion, as catalyst.